Magnetic device for transforming an oscillatory motion into a rotary motion

ABSTRACT

AN OSCILLATING MAGNET MOVES ALONG RADIAL ARMATURE PORTIONS OF A WHEEL WHICH ARE SLATED TO THE PLANE OF OSCILLATION AND TO THE PATH OF THE MAGNET TO FORM AIR GAS OF DIFFERENT WIDTH SO THAT THE WHEEL IS STEPWISE ROTATED WHILE THE MAGNETIC COUPLING BETWEEN THE MAGNET AND AN ARMATURE PORTION IS ESTABLISHED AT THE BEGINNING OF A STROKE AND INTERRUPTED AT THE END OF THE STROKE WHERE THE AIR GAP IS WIDEST, WHEREUPON THE NEXT FOLLOWING ARMATURE PORTION IS MAGNETICALLY COUPLED WITH THE MAGNET.

Oct. 5, 1971 BERTSCH ETAL 3,609,958

MAGNETIC DEVICE FOR TRANSFORMING AN OSCILLATORY MOTION INTO A ROTARYMOTION Filed Margh 9, 1970 3 Sheets-Sheet 1 mmvron H4003 F. lit/U560 BY"our 604! Oct. 5, 1971 ETAL 3,609,958

MAGNETIC DEVICE FOR TRANSFORMING AN OSCILLATORY MOTION INTO A ROTARYMOTION Filed March 9, 1970 3 Sheets-Sheet 73 INVENTOR. 0400) F1 [3017'BY "N237 6M Filed March 9, 1970 .Oct. 5, 1,71 H BERTSCH ETAL 3,609,958

MAGNETIC DEVIC 0R TRANSFORMING AN OSCILLATORY MOTI INTO A ROTARY MOTION3 Sheets-Sheet 5 United States Patent 3,609,958 MAGNETIC DEVICE FORTRANSFORMING AN OSCILLATORY MOTION INTO A ROTARY MOTION Hanns F. Bertschand Horst Graf, Schwenningen, Germany, assignors to Friedrich MautheG.m.b.H., Schwenningen, Germany Filed Mar. 9, 1970, Ser. No. 17,796

Claims priority, application Germany, Mar. 7, 1969, P 19 11 651.9; Feb.13, 1970, P 20 06 549.0 Int. Cl. G04c 3/00 US. Cl. 58-23 D 14 ClaimsABSTRACT OF THE DISCLOSURE An oscillating magnet moves along radialarmature portions of a wheel which are slanted to the plane ofoscillation and to the path of the magnet to form air gaps of differentwidth so that the wheel is stepwise rotated while the magnetic couplingbetween the magnet and an armature portion is established at thebeginning of a stroke and interrupted at the end of the stroke where theair gap is widest, whereupon the next following armature portion ismagnetically coupled with the magnet.

BACKGROUND OF THE INVENTION The invention relates to a magnetic devicefor transforming an oscillatory motion into a rotary motion of the typeused for driving clockworks, particularly of electric watches. Thedevice may be used for driving the balance wheel of a watch, or formagnetically controlling the escapement mechanism of spring drivenwatches and clocks.

A watch using an oscillating tuning fork with magnetically controlledescapement wheel is known in which the wheel has inner and outercircular rows of teeth consisting of a magnetizable material. Adisadvantage of the known constructions is that they are notself-starting. Since the oscillator magnet produces a torque in bothdirections of rotation of the wheel, the wheel has no preferreddirection of rotation, so that it has to be started until reaching anumber of revolutions synchronous with the frequency of the oscillatormagnet.

Another magnetic escapement device is known in which adjacent portionsof armature portions of the wheel have different dimensions so that themagnetic force has a greater effect in one direction of rotation than inthe other. However, the difference between the magnetic forces acting inopposite directions is so small that the mechanism can only be startedwithout any load. Since the driven pointers produce a reverse torque,the available force differences are hardly suflicient for self-starting.It is even possible that the reverse torque .of the pointers pushes thewheel back due to the fact that the magnetic force decreases with asquare of the distance.

In another construction of the prior art, which is designed formechanically oscillating drive elements, the wheel has coupling teethwhich are so shaped as to favor one direction of rotation. Due to thelow difference between the opposing forces, the device has a very lowefficiency.

SUMMARY OF THE INVENTION It is one object of the invention to provide aself-starting magnetic device for stepwise driving a wheel.

Another object of the invention is to provide a magnetic device fortransforming an oscillatory motion into rotary motion which producessufficient torque to drive a 'large clock for example a wall clockwithout substantially dampening the oscillation of the oscillatory drivemeans.

Another object of the invention is to provide a magnetic 3,609,958Patented Oct. 5, 1971 device for transforming an oscillatory motion intoa rotary motion which operates at high efficiency, and with greatreliability.

In contrast to the prior art, the present invention relies on air gapsof varying width for obtaining different magnetic forces acting inopposite directions of rotation of the wheel. Since the magnetic forceis proportional to the square of the distance, a variation of the airgap is very effective. When the air gap is increased, the magneticcoupling force between the oscillator magnet and the armature portion ofthe wheel is reduced, and when the air gap is wide enough, the magneticcoupling is interrupted so that the oscillatory magnet can perform areturn stroke without any magnetic effect on the driven wheel which isconsequently rotated only in one direction, and easily starts.

In accordance with the invention, one or two oscillatory magnets, andmagnetizable armature portions of the driven wheel are arranged so thatthe air gap between the same varies its width along the path of movementof the oscillatory magnet in such a manner that during rotation of thewheel in one direction of rotation, the magnetic coupling of theoscillatory'magnet with the respective armature portion magneticallycoupled therewith, is reduced, while it again increases for the nextfollowing armature portion.

One embodiment of the invention comprises oscillatory means including amagnet means swinging in a first plane along a path, the path beingpreferably part-circular; and a driven wheel having a circumferentialrow of equidistant temporarily magnetizable armature means.

The wheel has a plurality of positions in which successive armaturemeans are located in the region of the path of the magnet means defininga first angle with the path, whereby the magnetic force between themagnet means and the respective armature means causes stepwise turningof the wheel in one direction of rotation at least during a workingstroke of the magnet means.

The armature means also define a second angle with the plane ofoscillation of the magnet means, so that during rotation of the wheel inone direction of rotation, a magnetic coupling force between the magnetmeans and the respective cooperating armature means is established atthe beginning of a stroke, decreases during the stroke due to thewidening of the air gap, and is interrupted at the end of the strokewhereupon the magnet means magnetically couples with the next followingarmature means.

In one embodiment of the invention there is only one oscillating magnetprovided which during opposite strokes cooperates with two armatureportions of the respective armature means. Each armature meansincludes afirst armature portion, a second armature portion and a third armatureportion connected with the first and second armature portions. The firstand second armature portions converge in outward direction and beingconnected at the extremities thereof by the third armature portion. Thearmature portions form a circular zig-zag shaped magnetizable structureabout the center portion of the wheel, which preferably includes spokesto which the inner ends of the first armature portions are connected.The magnet moves during each stroke substantially along a first armatureportion and during the following opposite substantially along the secondarmature portion, and since the same define different angles with thepath of the magnet, the wheel is driven. The first armature portionsdefine small angles with the plane of oscillation of the magnet betweenthe reversing points of the oscillation of the magnet, while the thirdarmature portion, which connects the first and second armature portionsis steeply slanted in opposite direction in relation to the plane ofoscillation.

For an oscillatory movement of the magnet means at a frequency between15 and 40 hertz, and with an amplitude between and 30, the magneticcoupling between the magnet means and the annular zigzag-shaped orsinusoidal armature structure is maintained so that the wheel iscontinuously rotated, and stopped after each step. The flat slant of thefirst and second armature portions has the effect that the magneticcoupling is increased during an oscillatory stroke in one direction anddecreased during the oscillatory stroke during the opposite direction.Since at the reversing points, the third armature portion having anopposite steep slant is coupled with the magnet means, the coupling ofthe magnet means with the next following armature portion prevails, sothat the wheel is forced to rotate in one direction of rotation only.

The arrangement has the advantage that the wheel can be started withoutadditional starting energy and in a preferred direction of rotation.Furthermore, a wheel has the effect of stabilizing the amplitude ofoscillation of the oscillatory magnet, in the event that the same swingsbeyond the armature structure in radial direction in relation to thewheel, since a reduction of the coupling force between the magnet meansand the armature portions prevents an increase of the amplitude ofoscillation of the magnet means.

The spokes of the wheel are located outside of range of the amplitude ofoscillation of the magnet means so that they are not magneticallycoupled with the same.

In another embodiment of the invention, the oscillatory means includetwo magnets which are spaced along the part-circular path along whichthey swing. Each armature vmeans includes two armature portions spacedin circumferential and radial direction of the wheel, and preferablyprojecting in opposite radial directions from a ring along which theyare staggered in circumferential direction. The slant of the armatureportions to the plane of oscillation and to the path of oscillation areselected so that during the rotation of the wheel, alternately themagnetic coupling force between one of two magnets with their respectivecooperating armature portion prevails. During each stroke in onedirection, one of the magnets is eflective to drive the wheel, and theother magnet is ineffective. During the reverse stroke, the magneticcoupling is reversed. Due to the different width of the air gaps, theforce produced by the respective non-elfective magnet is comparativelylow.

Advantageously, the two magnets are arranged on the oscillatory means ata distance along the path which corresponds to the distance of thesmallest air gap from the greatest air gap along the respective armatureportion.

The armature portions have between the region of the greatest andsmallest air gaps, effective drive portions which are slanted to thepath of oscillations, and, when coupled with the respective magnet,produce a turning moment on the Wheel.

The wheel can be constructed so that it is shifted one or two steps foreach oscillation, and the shifting of the Wheel may take place in theregion of the reversing points of oscillation, or in the region of thecenter of the oscillation. It is particularly advantageous to arrangethe slanted part of the armature portions in such a manner that theshifting of the wheel takes place when the oscillatory magnet movesthrough the zero position at the center of the oscillation path. In thisevent, the oscillatory means has the greatest kinetic energyduringswitching from one armature portion to the other. In order to obtain insuch an arrangement a reliable shifting function even if the oscillationamplitude is different, it is advantageous to extend the ends of thearmature portions in the direction of the path of the magnet or magnetsso that the magnet is guided before and after arriving at the reversalpoints Without any shifting action on the wheel, until the magnetarrives at the center part of the respective armature portion which isslanted to the plane of oscillations so that a magnetic torque isproduced.

When the two armature portions, which cooperate with two magnets,project in opposite substantially radial directions from aconnectingring, theinner andouter armature portions are slanted to thepath of oscillation at different angles, and are staggered incircumferential direction. The greatest gap is provided in the region ofthe connecting ring. The inner and outer ends of the armature portionspreferably extend in the direction of the path of oscillation of themagnets for stabilizing the amplitude of oscillation.

The influencing of the magnetic coupling between the magnets and thearmature portions by variations of the air gap, can be further improvedby using armature portions whose width and thickness varies, forexample, the width of the armature portions decreases from the region ofthe smallest air gap to the region of the greatestair gap.

A wheel according to the invention can be manufactured in a simplemanner by punching or etching, or in other manners, of temporarilymagnetizable material such as soft iron, which is transversely stampedand deformed to saw tooth shape, so as to be slanted to the plane ofoscillation. U-shaped or V-shaped impressions may be stamped into thearmature portions.

The oscillatory means which carries the magnet or magnets, preferablyoscillates angularly about an axis which is parallel to the axis of thewheel. However, a leaf-spring oscillator or a tuning fork oscillator canalso be used which is provided in suitable manner with permanent magnetmeans.

The device of the invention canadvantageously be used for a clock orwatch, particularly with a transistor controlled clockwork in which theoscillatory magnet controls the step of the wheel in the manner of thebalance wheel. In this event, additional control magnets form part ofthe oscillatory means, which are controlled in a known manner by anelectrically energized coil arrangement. A control magnet induces in acontrol coil a pulse, which opens or closes a control transistor whichis provided in the circuit of a drive coil whose field produces a drivetorque acting on the oscillatory means which is restrained by a spring.The device of the invention may also be used for magneticallycontrolling the escapement mechanism of a spring driven watch or clock.

The novel features which are considered as characteristic for theinvention are set forth in particular in the appended claims. Theinvention itself, however, both as to its construction and its method ofoperation, together with additional objects and advantages thereof, willbe best understood from the following description of specificembodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a fragmentary side elevationillustrating a first embodiment of the invention;

FIG. 2 is a fragmentary plan view of the embodiment of FIG. 1;

FIG. 3 is a front elevation of the embodiment of FIGS. 1 and 2;

FIG. 4 is a plan view illustrating a driven Wheel used in the embodimentof FIGS. 1-3 on a larger scale;

FIG. 5 is a front view of the wheel of FIG. 4;

FIG. 6 is a developed view illustrating a peripheral armature portion ofthe Wheel of FIGS. 4 and 5;

FIGS. 7, 8, 9 and 10 are fragmentary plan vieWs illustrating a secondembodiment of the invention in suc cessive operational positions; and

FIG. 11 is a cross-sectional view taken on line A-B in FIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to theembodiment of FIGS. 1-6, an oscillatory means is mounted on a pair ofsupport plates 1 and 2 for oscillatory movement about the axis of ashaft 3. The oscillatory means further include two carrier plates 4 and5 secured to shaft 3. Carrier plate 4 supports a drive magnet 9 at oneend, and a control magnet 7 at the other end. A corresponding controlmagnet 8 is secured to carrier plate 5 opposite control magnet 7. A coilspring 3 is secured at one end to the hub of carrier plate 4, and at theother end to a lug on supporting plate 1, and applies a torque to theoscillatory means 3, 4, 5, 7, 8, 9 acting in one direction ofoscillation.

Support plates 1 and 2 further mount a shaft 10 which carries the drivenwheel 11. The wheel is stepwise rotated in one direction, as will bedescribed hereinafter in greater detail, so that shaft 10 is driven anddrives through a worm 12 and a worm gear 13, the movable wheels of aclockwork, not shown.

An inertia wheel 14 is mounted for rotation on a flange 15 of shaft 10,and is frictionally connected with the same.

Coil means 16 which may consist of drive coils, and control coils woundbifilar, coaxial or disk shaped, produce together with the control anddrive magnets 7 and 8 magnetic field pulses which oscillate theoscillatory means at a frequency between 15 and 40 hertz, and at anamplitude between 10 and 30. During this oscillation, magnet 9 movesalong a part-circular path, illustrated in FIG. 2 by double arrow a.

Magnet 9 cooperates with and drives, a wheel 11 which is preferablystamped in one piece out of a temporarily magnetizable material. Wheel11 has a hub portion 11c from which spokes 11d outwardly project at anangle to the respective radial vector. Each spoke 11d is integral withan armature portion 11a which is connected at its outer end by anarmature portion 11:; with the armature portion 11b, whose inner end issecured to the inner end of the respective following armature portion11a. In this manner, the three armature portions 11a, 11b and 11e forman annular zig-zag shaped armature structure around the periphery of thewheel.

FIGS. 4 and 6 show the relative angular positions of the armatureportions 11a, 11b and 11a in relation to the path a along which thearmature portions magnetically cooperate with the oscillating magnet 9.Due to the slant of armature portions 11a and 11b to the plane ofoscillation in which the path a is located, the air gap between magnet 9and armature portions 11a and 11b, respectively, increases during eachoscillatory stroke of magnet 9 so that the magnetic coupling force isreduced until magnet 9 arrives at the respective reversing point wherethe short, connecting armature portion 11a is located, which is inclinedat a steep angle to the plane of oscillation a, and which is positionedto suddenly reduce the width of the air gap so that the oscillatorymagnet always drives wheel 11 in the same direction of rotation..

Referring now to the embodiment of FIGS. 7 to 11, an oscillatory means17 is partly shown which includes two magnets 19 and 20, swinging in thedirection of the double arrow b about an axis 18 which is parallel tothe axis of the driven wheel 22. Magnets 19 and 20 are spaced .along thecircular path along which they move in the direction c or d.

The wheel 22 has inner armature portions 24 and Outer armature portions25. The inner ends of the inner armature portions 24 are connected withthe central hub portion of wheel 22, and the outer ends of armatureportions 24 and the inner ends of armature portions are connected by aring 23 so that armature portions 24 are spokes carrying the ring 23with the outer armature portions 2 The inner armature portions 24 andthe outer armature portions 25 are constructed in such a manner that themagnetic coupling is switched from an inner armature to an outerarmature portions, and from an outer armature portion to an innerarmature portion in the central neutral position of the oscillatorymeans 17 with magnets 19 and 20 which has constructive and kinematicadvantages since the oscillatory means 17 has the greatest kineticenergy when moving through the neutral central position.

The outer armature portions 25 have an inner end portion 25a, a slantedcentral part 25b, and an outer, radial end portion 25c. The axis 18 andthe path of oscillation of magnets 19 and 20 is selected so that magnets19 and 20 move substantially in radial direction of wheel 22 along atangent on the curved path of magnets 19 and 20 being located in aradial plane passing through the center of wheel 22. Consequently, thepart circular path of the magnets 19, 20 is perpendicular to the ring23.

The inner armature portions 24 have two parts 24a and 24b which areslanted different angles in relation to the path of magnet 19. The innerpart 24a of the respective inner armature portions 24 which cooperateswith magnet 19, is located in the path of movement of magnet 19, as bestseen in FIGS. 8 and 9. The part 24 of the respective operative innerarmature portion 24 is slanted to the path.

As shown in FIG. 11, the armature portions 24, 25 are also deformed tobe partially slanted to the plane in which magnets 19 and 20 oscillateabout the axis 18. The air gap between the end face of magnet 20 and thepart 25a of armature portions 25 increases during movement of magnet 20,and the air gap between part 24b of armature portion 24 and magnet 19increases in the opposite direction.

Near the end position of the oscillatory means 17, shown in FIG. 7,magnet 20 is magnetically coupled with the outer end part 250 of anouter armature portion 25. When the oscillatory means moves in thedirection of the arrows c, magnet 20 cooperates with a slanted middlepart 25b, attracting the Same by a magnetic coupling force so that wheel22 is turned a step in clockwise direction. When magnet 20 is in theregion of the ring 23 and part 25a, the air gap is the greatest, and themagnetic coupling between magnet 20 and parts 25a, 23 can beinterrupted.

In the following position shown in FIG. 8, magnet means 19, 20 approachthe other end position shown in FIG. 9. In the position of FIG. 8,magnet 20 cooperates with ring 23 and with inner part 25a of armatureportion 25 over a large air gap, while magnet 19 is magnetically coupledwith part 24a of the next following inner armature portion 24 due to thesmall air gap in this region. Thereupon, magnet 19 moves to the endposition of FIG. 9 along the inner portion 24a of the respective innerarmature portion 24 out of the position of FIG. 8. When the oscillatorymeans 17 swings back from the end position shown in FIG. 9 in thedirection of the arrow d, at first no turning moment is applied to theWheel 22, since magnets 19 and 20 move in the directions of the innerparts 24a and 25a of the respective inner and outer armature portions24' and 25. During continued movement toward the other end positionshown in FIG. 10, the magnetic coupling between magnet 20 and armatureportion 25 is interrupted while magnet 19 turns wheel 22 in clockwisedirection while being magnetically coupled with the part 24b of armatureportion 24. Due to the angular displacement of wheel 22, magnet 20 isnow in the region of the outer part 25c of the next following outerarmature portion 25, and is magnetically coupled with the same due tothe fact that the air gap is small in this region. Magnet 19, however,is now in the region of the greatest air gap with ring'23, so that thefollowing angular displacement of the wheel 22 by the action of magnet20 interrupts the magnetic coupling between magnet 19 and armatureportion 24'. The position of FIG. 10 corresponds to the position of FIG.7 after turning Wheel 22 in an angular step so that the above-describedoperations can be repeated for rotating wheel 22 under the control ofthe oscillating magnet means 19, 20.

It will be understood that each of the elements de-. scribed above, ortwo or more together, may also find a useful application in other typesof magnetic devices f r transforming oscillatory motion into rotarymotion, differing from the types described above.

While the invention has been illustrated and described as embodied inoscillating magnet means cooperating through varying air gaps witharmature portions of a wheel for rotating the same, it is not intendedto be limited to the details shown since various modifications andstructural changes may be made without departing in any way from thespirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can, by applying current knowledgereadily adapt it for various applications without omitting featuresthat, from the standpoint of prior art, fairly constitute essentialcharacteristics of the generic or specific aspects of this inventionand, therefore, such adaptations should and are intended to becomprehended within the meaning and range of equivalence of thefollowing claims.

What is claimed as new and desired to be protected by Letters Patent isset forth in the appended claims.

We claim:

1. Magnetic device for transforming an oscillatory motion into a rotarymotion, comprising, in combination, oscillatory means and includingmagnetic means swinging in a plane along a path; and a driven wheelhaving a circumferential row of temporarily magnetizable armature means,said wheel having a plurality of positions in which successive armaturemeans are located in the region of said path defining a first angle withsaid path whereby the magnetic force between said magnet means and therespective armature means causes stepwise turning of said wheel in onedirection of rotation, and defining a second angle with said plane sothat during rotation of said wheel in said one direction, a magneticcoupling force between said magnet means and the respective cooperatingarmature means is established at the beginning of a stroke, decreasesduring the stroke due to the widening of the air gap, and is interruptedat the end of the stroke whereupon said magnet means magneticallycouples with the next following armature means.

2. A device as claimed in claim 1 wherein said oscillatory means has anaxis; wherein the axis of said wheel is parallel to said axis of saidoscillatory means so that said wheel is located in a plane parallel tosaid plane of said magnet means except for said armature means which areslanted at said second angle to said plane; and wherein the respectivearmature means which cooperates with said magnet means is slanted atsaid first angle to a tangential plane on said path.

' 3. A device as claimed in claim 1 wherein said wheel has a centralportion and a peripheral portion formed by said plurality of armaturemeans; wherein each armature means includes a first armature portion, asecond armature portion, and a third armature portion, connecting saidfirst and second armature portions, said first and second armatureportions alternately converging in outward and inward radial directionsand being connected at the extremities thereof by said third armatureportion, said first and second armature potrions defining first angleswith said path and forming a circular sinusoidal or zig-zag shapedmagnetizable structure about said central portion; wherein said firstand second armature portions are slanted at second angles to said planebetween the reversing points of the swinging motion of said magnet meansalong said path; and wherein said third armature portion is steeplyinclined to said plane and is slanted to the same in a directionopposite to the slant of said first and second armature portions to saidplane.

' 4. A device as claimed in claim 3 wherein said central portion of saidwheel includes a hub portion and a plurality of spoke portions havingouter ends connected with the inner ends of said first armature portionsand being spaced from said path and said plane so that no substantialmagnetic force is applied by said magnet means to said spoke portions.

5. A device as claimed in claim 1 wherein each armature means includesan inner armature portion and an outer armature portion oppositelyslanted at first angles to said path; wherein said magnet means ismovable along a part-circular path and includes outer and inner magnetsspaced in the direction of said path and magnetically cooperating withsaid outer and inner armature portions, respectively, said outer andinner armature portions being slanted at opposite second angles to saidplane so that during a stroke of said oscillatory means with saidmagnets in one direction the magnetic force exerted by said outer magneton said outer armature portions turns said wheel one step in said onedirection of rotation while said inner magnet is ineffective, due to thewidth of the respective air gap, and so that during a stroke in theopposite direction, the magnetic force exerted by said inner magnet onsaid inner armature portions turns said wheel one step in the samedirection of rotation, while said outer magnet is ineifective due to thewidth of the respective air gap.

6. A device as defined in claim 5 wherein said outer and inner magnetsare mounted on said oscillatory means at a distance in the direction ofsaid path which is substantially the distance between the smallest partand the widest part of the air gaps between said magnets and saidarmature means; and wherein said outer and inner armature potrions havebetween said smallest and widest parts of said air gaps, central partsslanted to said path and said plane.

7. A device as claimed in claim 6 wherein said slanted central parts ofsaid inner and outer armature portions are disposed in the middle ofsaid path; and wherein each of said armature portions has two endportions at opposite ends of said central part which extend in thedirection of said path when the respective armature portion magneticallycooperates with the respective magnet.

=8. A device as claimed in claim 7 wherein said wheel has an axis ofrotation parallel with said axis of said oscillatory means, a hub partfrom which said inner armature portions outwardly project, a ringconcentric with said axis and secured to the outer ends of said innerarmature portions, and to the inner ends of said outer armatureportions, said outer and inner armature portions being staggered incircumferential direction along said ring.

9. A device as claimed in claim 8 wherein the air gaps between saidouter magnets and outer armature portions, and also between said innermagnets and said inner armature portions are widest in the region ofsaid ring.

10. A device as claimed in claim 9 wherein the width of said armatureportions decreases from the region where the air gap is smallest to theregion of the widest air gap near said ring for reducing the magneticforce.

11. A device as claimed in claim 7 wherein said wheel and said armatureportions are made of magnetizable sheet material, and wherein saidcentral parts of said armature portions are deformed out of the plane ofsaid sheet material so as to be slanted to said plane in which saidmagnet means oscillates.

12. A device as claimed in claim 1 wherein said oscillatory means has anaxis in its central region and said magnet means at one end, andincludes control magnet means located at the other end thereof; andcomprising elastically energizable coil means cooperating with saidcontrol magnet means for causing oscillation of said oscillatory meansfor rotating said wheel for driving a clockwork.

13. A device as claimed in claim 1 wherein said magnet means is a singlemagnet; wherein each armature means includes two armature portionsslanted at opposite angles to said path, and being slanted to eachother; and wherein said magnet moves along one of said armature portionsduring a stroke in one direction, and along the other armature portionduring a stroke in the opposite direction.

14. A device as claimed in claim 1 wherein said mag- References Citednet means mcludes twomagnets spaced 1n the dlrectlon FOREIGN PATENTS ofsaid path; wherein each armature means mcludes two armature portionsspaced in circumferential and radial 660,581 11/1951 England 58 116 Mdirections of said Wheel; and wherein said magnets move 5 RICHARD BWILKINSON Primar [Examiner along said two armature portions,respectively, of one y armature means during each stroke in onedirection and SIMMONS, Assistant EXamineI' along said two armatureportions of the next follow- US Cl XR ing armature means during thefollowing stroke in the opposite direction. 10 58116; 74-126; 310-37

